1. Field of Technology
The present invention generally relates to a microfilm duplicating apparatus and, more particularly, to a blip marking recorder in the microfilm duplicating apparatus for imprinting blip markings on a duplicate microfilm being duplicated.
2. Description of the Prior Art
From, for example, the Japanese Laid-open Patent Publication No. 58-149572 and the U.S. Pat. Nos. 4,561,769 and No. 4,600,291, and the U.S. Pat. No. 4,671,648, an electrophotographic microfilming apparatus is well known, which apparatus can be advantageously utilized, for the purpose of documentation and storage of documents, for recording images of documents on a reduced scale on an electrophotographic microfilm.
While the microfilming apparatus of the type referred to above and utilizing the 2-reel microfilm cassette of a type disclosed in, for example, the U.S. Pat. Nos. 4,572,649 and 4,685,638, is satisfactory, office documentation at different sections or departments of an establishment such as an office, a company or an institute would be expedited if identical recordings of the particular documents are readily available at the respective sections or departments. If only one recording of the documents is available in the establishment, it will often happen that an office clerk belonging to a particular section or department has to resort to the different section or department where the recording is kept.
If recording of documents is made on a photographic material such as, for example, a microfiche or a roll of film utilizing silver halide materials, the identical recordings of the documents can be relatively quickly and efficiently prepared by the use of a well-known contact printing technique wherein an unexposed photographic recording medium is held in contact with the photographic master recording at the time of exposure to the illuminating light and is, thereafter, developed and fixed to produce images identical with those born in the master recording.
However, when it comes to the electrophotographically recorded microfilm, any technique similar to the photographic contact printing technique cannot be employed in making duplications of the electrophotographically recorded microfilm because the electrophotographic recording system requires a process of electrostatic charging, exposure, development and fixing all sequentially subjected to the electrophotographic recording medium.
In view of the foregoing, when documents are to be recorded or duplicated on the encased electrophotographic recording medium, that is, the electrophotographic recording medium contained in the 2-reel cassette, the number of the microfilm cassettes required has to be determined before the documents are actually recorded, or very time-consuming and complicated procedures are required at the time the necessity arises for one or more extra microfilm cassettes having the identical recordings of the particular documents. Should one or more extra microfilm cassettes be needed, for example, for distribution to the different sections or departments of the establishment, and if the necessity has arisen after one microfilm cassette had been prepared, those jobs which have been executed for the preparation of such one microfilm cassette have to be repeated.
Accordingly, in a microfilm duplicating system wherein no contact printing technique can be employed, each of the images recorded on the master microfilm must be optically reproduced at equal magnification and then projected onto the unexposed microfilm for duplication.
Thus, where the optical system is used, numerous requirements not hitherto encountered have to be satisfied in view of the fact that each frame of the microfilm which bears the respective image to be duplicated is very minute. Such requirements include that the minute image must be reproduced at 1:1 magnification, a high resolution must be attained, and the optical system must be so designed as to cope with various limitations imposed by the microfilm cassette, where duplication is desired to be made with the use of the previously discussed electrophotographic microfilms encased in the respective cassettes, because of the relationship with the processing head operable to execute an electrophotographic process from the electrostatic charging to the fixing, particularly the relationship with the electrophotographic development, and also because of the presence of limitations resulting from the position of the cassette specified to achieve a stabilized movement of the microfilm.
In view of the foregoing, the assignee of the present invention has suggested a novel microfilm duplicating apparatus satisfying the numerous optical requirements for duplicating images, recorded on a master microfilm, on a duplicate microfilm at a high resolution, which apparatus is provided with a compact and simple photographic optical system.